1 Field of the Invention
The present invention relates generally to a shimming gage, and, more particularly, to a bevel gear shimming gage.
2. Description of the Prior Art
Cooperating bevel gears provide a unique arrangement whereby the axes of rotation for one shaft may be translated to any other intersecting desired axis of rotation. Consequently, bevel gear arrangements have enjoyed widespread acceptance in industry in general and are particularly commonly employed with high speed turbine engines.
Since the axes of rotation for the bevel gears usually intersect at an oblique angle, in practice it is necessary to provide shims, or spacers, around the bearings which carry the bevel gears in order to properly axially position the bevel gears. The use of shims compensates for manufacturing tolerances in the construction of the bevel gear and the bevel gear housing and, without the use of shims, the gear teeth engagement between the bevel gears will ordinarily mismatch and subject the bevel gears to excessive stress and mechanical wear and tear. Continued operation of mismatched bevel gears may result in bevel gear failure which is particularly disasterous at high speed bevel gear operation.
The previously known bevel gear shim sets have proved to be not only expensive in construction, but also awkward and time consuming in operation. Such sets have usually comprised three groups of multi-piece gages and three separate shim assemblies. A preliminary assembly utilizing a various number of loose gaging pieces is first assembled within the bevel gear housing to obtain the dimensions of the thrust side shims. This preliminary assembly is then dismantled and the thrust side shims are ground to the desired thickness and installed in the bevel gear housing. A second bevel gear shim assembly is then assembled within the bevel gear housing with the already ground thrust shim in order to determine the opposite end third shim. The third and final shim assembly is then constructed in the bevel gear housing with the already dimensioned thrust and third shim. The dimensions of the third and fourth shims are determined from the third bevel gear shim assembly and these shims must then be ground before final engine assembly can be completed.
Since each shim must be sequentially ground to size before the next shim dimension can be determined, the previously known bevel gear shim gages have proven to be time consuming in operation. For example, often four hours or more are required to determine and grind the four shims required in a single bevel gear arrangement. Moreover due to the multiple assemblies required with the previously known bevel gear shim gages, these gages have been not only awkward in operation but also expensive in construction.